Monthly Archives: August 2015

July 2015: The Japan International Research Center for Agricultural Sciences (JIRCAS)

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Wednesday 22nd July 2015

Back in July I was delighted to visit the Japan International Research Center for Agricultural Sciences, or JIRCAS, in Tsukuba, thanks to my friend Dr Marcy Wilder who is involved in shrimp aquaculture there. At first glance there is no obvious link between JIRCA and scuba diving, but as I prepare to start an online MSc in Sustainable Aquaculture with the University of St Andrews in Scotland next month, I’m more than keen to start delving into the world of aquaculture here in Japan.

JIRCAS is what’s known as an “Incorporated Administrative Agency” that comes under Japan’s Ministry of Agriculture, Forestry and Fisheries and plays a key role in international collaborations in agriculture, forestry and fisheries research in Japan.  JIRCAS’s aim is to provide solutions to global food and environmental problems and a stable supply of agricultural forestry and fishery products and resources.

In the fields of fisheries and aquaculture, research at JIRCAS consists of three important areas: the sustainable utilisation of living aquatic resources, technology that doesn’t negatively impact on biological diversity, and socioeconomic studies on the marketing and distribution of aquatic products.

Today shrimp farming is a significant industry worldwide and production is increasing rapidly to meet demand.  The industry has grown in Southeast Asia in particular, but the farming methods involved have often been controversial and resulted in environmental problems and a shortage of shrimp spawners.  Marcy is currently working as a senior research scientist at JIRCAS.  Her research covers areas such as reproduction, osmoregulation and technology to control female maturation in captivity. She is also developing land-based re-circulating systems with zero impact on the environment, and her technology is being used to produce shrimp in the mountains of Niigata prefecture near Myoko.  As she showed me around the labs, I got to see some of the shrimp she is working on and hear more about her research, including the current status of freshwater prawn culture in Vietnam and the light perception capability of shrimp. I was really impressed, not just by the vast amount of research that’s going into a single species, but also by the possibilities Marcy’s technology entails, and hope that its implementation will contribute to the sustainability of shrimp aquaculture and to an even better environment.

July 2015: The Return to Kozushima, Japan

Monday July 27th – Wednesday July 29th, 2015

Kozushima is one of the islands in the Izu Island chain south of Tokyo.  About 3 hours and 45 minutes from the capital by fast boat, its turtles, coral gardens and schools of fish are a sight to behold. The island is an idyllic setting backed by vibrant blue summer skies and lazy azure waters that are peppered with a patchwork of coral reefs and rocky structures. There are many dive spots in and around Kozushima for the curious diver to explore, and below are some of them.  Enjoy the diverse marine life here in the Pacific Ocean, then relax in this warm and tiny paradise so close and yet so different to Tokyo.

Naganne: Located about 10mins away from the mainland, Naganne is a sheltered area near Miura Bay.  Descending to around 5m and swimming over a carpet of shallow rocks, we came to an open spot at about 12m.  Although the site’s maximum depth is around 30m, we spent time exploring the relatively flat 12-14m area.  With a good range of marine species, Naganne is a melting pot of marine life, with spectacular underwater scenery and an abundance of rocks, all of which are home to a wide array of corals and fish.  A porcupine fish peered out at us from his dark crevice, while blue and white nudibranchs Hypselodoris festiva and Chromodoris orientalis were just a few of the many lovely creatures to commonly grace Naganne’s rocky seascape, and no way was I in any hurry to leave as I panned my camera across the entire scene from various angles and hung around for a good while.  The rocks, decorated with banded coral shrimp and two species of the nudibranch Ceratosoma trilobatum, were also home to a huge and sleepy Japanese wobbegong, and created a beautiful stage on which the shimmering sun rays danced nimbly. Lobsters also gave themselves away, their eyes reflecting in the torchlight.

Sanju: Healthy coral of every shape and colour thrive along the walls where the ocean floor drops into oblivion, while schools of knife fish, angelfish and Centropyge interrupta (Japanese angelfish) feed off the area.  Famed for its resident white-saddle goatfish, spotted tail mornings and golden-striped groupers, Sanju has much to offer despite its relatively standard and ordinary appearance as the dive begins at around 5m.  Sanju is also a great place for those who like endless scores of nudibranchs and decorator crabs scuttling about their business, and adding to the site is a comprehensive collection of sponges and soft corals, providing fantastic photo opportunities no matter which area you decide to explore. Streaks of sunlight also glisten through the 12-15m area, making the site all the more attractive. Dragon morays call Sanju home, neon damselfish cruise the sides of the many rocks, and other areas are frequented by thread-sail filefish.  Meanwhile, like an oasis of life, a sac anemone hosted a couple of anemone fish and clownfish.  

Urazakune:  Expect steep walls and congregations of pelagic fish here at Urazakune.  The current can be quite strong and while drifting along the slopes and walls we got to admire schools of knife fish in the blue.  Friendly turtles also love Urazakune and can be seen heartily munching on sponges in the safety of the rock gardens, while chicken grunts become visible in the distance.  Hovering over the rocks are anthias, fusiliers and lots of clownfish in their host anemones.  The currents bring nutrients to feed the area and a range of sponges have all flourished.  The rocks provide shelter at every level for countless thousands of reef fish and easily as many invertebrates.  Moray eels and Pacific burrfish can be found in or close to the dark recesses sheltering from the gentle current, while red-lipped morwongs feed off the area.  As the current slowly picks up, the fish seem to crowd every scene – the density of life here is something to behold with movement and colour everywhere.

Tsumari: This site has white sandy bottoms and can be stunning when visibility is good. The shallow areas are used for introductory dives, night dives and photo excursions. Only 5 minutes away from the dive shop by car, it’s found at the bottom of a cliff where divers walk into the water carrying their gear down a small flight of steps.  If the water is slightly choppy entry can be difficult, but once in the warm clear ocean it’s clear to see why Tsumari is one of Kozushima’s most popular sites. Its highlight is undoubtedly the white sand at around 12m where divers can lie on their backs and look up at the sun streaming through the water. There is also a small cluster of tree branches for squid to lay their eggs and a series of concrete beams that house lobsters.  It’s a sanctuary to a diverse array of marine life, set against a backdrop of teeming rocky outcrops. Ascending through the shallows we spotted beautiful squid and a cluster of their eggs, baby flatfish, spider crabs, nudibranchs (Hypselodoris festiva and Chromodoris orientalis) and yellow boxfish. Brown striped mackerel scad occasionally swirled around out of curiosity, while pufferfish hovered close to the rocks watching the world go by and a school of horse mackerel swam along in a perfect group.

Practical information

  • We took the overnight slow ferry from Takeshiba pier in Tokyo with Tokai Kisen ferries (  The boat leaves at 23:00 and costs around 6,000 – 7,000yen for a one-way ticket and a seat inside the boat although some people like to sleep on deck and blankets can be rented for 100yen each.
  • We booked our dives with Nangoku (  Three boat dives and one beach dive came to just under 30,000yen including tanks, weights and a guide.  Repeat customers also get a 5% discount on dives.
  • Diving equipment can be sent in advance from Tokyo for about 2,500yen using Kuroneko Takkyubin.
  • Immediately upon entering Nangoku there is a huge table surrounded by shelves of books, photos, posters and other decorations, with a reception desk on the left.  The area for diving equipment (washing, drying, hanging, storage) is on their deck upstairs overlooking the sea (Maehama Beach). A toilet and two showers (with shampoo and conditioner, no soap so remember to bring your own!) are also available, and the friendly staff will offer you copious amounts of cold tea.
  • Divers head to the  sites after loading the van with equipment and getting changed into wetsuits at Nangoku.  The boat Nangoku uses appears to be owned by local fishermen, is very spacious and flat with enough place to store gear.  Equipment is put on when the boat arrives at the dive sites.  Bring a towel, some sunscreen and a hat for the boat journey if you are worried about sunburn.
  • Lunch is not provided but after each dive there is time to check out some of the restaurants.  Next door to Nangoku on one side is Tears Blue that serves a range of rice and pasta dishes, coffee and cold drinks, and on the other is a soba noodle restaurant run by the Nangoku owner’s father. Expect to pay around 1,000yen for lunch. There is also an ice cream shop at the bottom of the road, 300yen for one scoop.
  • Divers are responsible for their own equipment.  When the dives are over, they are free to use the deck to change, wash, hang and dry their gear.  Cameras, dive computers and torches can be placed in a tray of cold water at the entrance to Nangoku.
  • We stayed on the 3rd floor of Nangoku for 3,000yen per night.  It’s not in the best condition but there is a fan, basic air conditioning, a huge room where guests sleep on the floor, towels to use and a toilet and kitchen area.  Nangoku can advise on dinner options, and there is a great izakaya (Japanese-style pub) serving excellent sashimi (raw fish).
  • A bit further up the coast from Nangoku is an outdoor hot spring which Nangoku will book for you and take you to.  Buses are available on the island, for 200yen per ride.
  • We booked the fast jetfoil back to Tokyo with Tokai Kisen ferries.  The boat leaves at 15:30 and gets to Tokyo at 18:40.  A single ticket costs 11,200yen.  There is one vending machine and the seats are like airplane seats.  It’s worth bringing a book and something to eat on board.

July’s dives 

Dive 1: Naganne: depth: 14.4m, dive time: 48mins, water temp: 27C, entry time: 09:56, exit time: 10:50, water visibility: 20m, used a 10L steel tank, 5mm wetsuit and 3kg back plate (1kg extra weight in pocket).  Star pressure: 180 bar, End pressure: 50 bar.  Saw Japanese wobbegong, blue and white nudibranchs Hypselodoris festiva and Chromodoris orientalis, white mouth moray eel, puffer fish, banded coral shrimp and two species of Ceratosoma trilobatum

Dive 2: Sanju: depth: 17.6m, dive time: 45mins, water temp: 24C, entry time: 11:33, exit time: 12:13, water visibility: 20m, average depth: 10.9m, used a 10L steel tank, 5mm wetsuit and 3kg back plate (1kg in pocket).  Start pressure: 180 bar, End pressure: 30 bar.  Saw knife fish, angel fish, white-saddle goatfish, spotted tail mornings and golden-striped groupers, decorator crab, dragon morays, thread sail filefish, clownfish and anemone fish.

Dive 3: Urazakune: depth: 14.6m, dive time: 48mins, water temp:23C, entry time:14:27, exit time: 15:18, water visibility: 20m, average depth: 9.7m, used a 10L steel tank, 5mm wetsuit and 3kg back plate (1kg in pocket).  Start pressure: 180 bar, End pressure: 50 bar.  Saw knife fish, turtles, anthias, fusiliers, clown fish, moray eels, Pacific burrfish and red-lipped morwongs

Dive 4; Tsumari: depth: 8.5m, dive time: 46mins, water temp: 26C, entry time: 09.53, exit time, 10:33, water visibility: 25m, average depth: 4.8m, used a 10L steel tank, 5mm wetsuit and 3kg backplate (2kg in pockets).  Start pressure: 180 bar, End pressure: 100 bar.  Saw squid and their eggs, baby flatfish, spider crabs, nudibranchs (Hypselodoris festiva and Chromodoris orientalis) and yellow boxfish, brown striped mackerel scad, horse mackerel and pufferfish